Wild rice species are invaluable resources for genetic improvement of cultivated rice. “Breeding super rice using double advantages of wide cross and polyploidization” is a novel pathway in rice breeding. To exploit the favorable genes of wild rice fully, a technical system composed of hormone treatment, repeated pollination, hybrid embryo rescue, and chromosome doubling was established for efficient creation of distant hybrids and allopolyploids. Using the technical system, the diploid and tetraploid interspecific hybrids between Oryza sativa L. and Oryza barthii A. Chev. were successfully established. Morphological traits such as lemma tip color, stigma color and exsertion, awn color and length of interspecific hybrids exhibited the characters of their wild rice parents. Some traits such as plant type and grain length were intermediate their parents. Overall, the fertility of hybrids was very low. The results of simple sequence repeat molecular marker detection indicated that the interspecific hybrids possessed the bands of both parents. After chromosome doubling, the grain size, and the seed‐set rates of the tetraploid interspecific hybrids increased significantly, but the tiller number per plant, panicle length, and the total grain number per panicle decreased significantly. The results showed the efficiency and importance of the technical system in establishment of distant hybrids and allopolyploids. The study provides novel germplasm resources for rice breeding and theoretical research.

中文翻译：

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Oryza sativa 和 Oryza barthii 之间二倍体和四倍体种间杂交的创建和鉴定


野生稻物种是栽培稻遗传改良的宝贵资源。“利用宽杂交和多倍体化的双重优势选育超级稻”是水稻育种的一条新途径。为了充分利用野生稻的有利基因，建立了由激素处理、重复授粉、杂交胚胎拯救和染色体加倍组成的技术体系，用于高效创造远距离杂交种和同种异体多倍体。使用该技术系统，Oryza sativa L. 和 Oryza barthii A. Chev 之间的二倍体和四倍体种间杂交。成功成立。稃尖颜色、柱头颜色和突出、芒色和种间杂交种长度等形态特征表现出其野生稻亲本的特征。一些性状，如植物类型和粒长，是它们的父母的中间性状。总体而言，杂交种的生育能力非常低。简单序列重复分子标记检测结果表明，种间杂交种具有亲本双方的条带。染色体加倍后，四倍体种间杂交种的粒径和结实率显著增加，但单株分蘖数、穗长和每穗总粒数显著下降。结果表明该技术系统在建立远距离杂交种和同种异体多倍体方面的效率和重要性。该研究为水稻育种和理论研究提供了新的种质资源。